What a Flame Sensor Is and Why It Matters

Scheduling your annual furnace maintenance helps keep your heating system operating up to 30 percent more efficient and helps extend the life of your furnace. But things could still go wrong, and when they do, you might feel like there is always something else.

This time it’s your heat exchanger, next time it’s your pressure switch. Now you need to replace your flame sensor.

What is a flame sensor, anyway?

A flame sensor is a crucial safety component on your gas heating system. During the ignition sequence, your gas furnace enters a process where either a hot surface ignitor or a spark actually ignites the gas. Once the gas is ignited, the flame sensor produces a current of electricity. The current is measured in micro amps. If the furnace’s control board fails to read the correct level of micro amps, the furnace will stop giving the system fuel to stop an explosion.

Over time, if the flame sensor is not cleaned properly, oxidation or carbon buildup can interfere with the flame sensor’s ability to work properly, which can cause the furnace to malfunction.

The way to diagnose if a soiled flame sensor is causing a furnace malfunction is to take a micro amp draw reading, which an expert heating technician can give you. If a dirty flame sensor is the offender, the furnace expert will clean the sensor with steel wool. If dirt was the sole factor, we will see a significantly higher amp reading. If the reading doesn’t change, the technician will continue with the heating system repair diagnostic process.

If you aren’t confident your heating system is going to outlast these last few weeks of winter, give Broad Ripple Service Experts a call and we’ll come out and perform a full furnace maintenance or a complimentary in-home estimate on a new heating system.

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